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Posted By: 68triton Valve spring lengths - 04/07/20 5:22 pm
Hi, I would be grateful if someone has the valve spring lengths for a 500cc DBD Clubman - road use.

The ones that I have received from reputable supplier measure as follows unfortunately due to Coronavirus they are now closed.
I ask this as there are different lengths from those in various manuals.

Outer = 1.750”
Inner = 1.725”

Many thanks
Posted By: Re: Valve spring lengths - 04/07/20 7:20 pm
Hi 68 Triton,
I have a workshop book from Terry Springs and it gives this info.
Outer 65-2494 wire dia.0.148" od 1.256" free length 1 11/16" total coils 5 3/4 full r/h wound
Inner 65-2495 wire dia 0.116" od .940" free length 1 50" total coils 6 l/h wound
This is from a book used in the workshop to check production.
Pat A

terry 451/488 the same springs for c15/b40/b44
Posted By: Kerry W Re: Valve spring lengths - 04/08/20 5:22 am
In the past I've always been more interested in the fitted length - enough not to be coil-bound at full lift, but little enough to allow some clearance from the piston by a small margin..with luck, that'll also give the designed poundages at lift and rest.
Posted By: GS John Re: Valve spring lengths - 04/08/20 9:51 am
From the BSA Gold Star Instruction manual:
Valve Springs (outer): free length 1.670 inches
fitted length 1.312 inches
(inner): free length 1.500 inches
fitted length 1.218 inches
Hope this helps
Posted By: 68triton Re: Valve spring lengths - 04/08/20 10:53 am
Hi Guys, Thanks for the replies.

I wanted to keep the specs, drifting away from these normally means trouble unless you 100% know what you are doing!

Are the original springs 'variable rate' ? There is so much on the market, just don't know of a reliable source.

Posted By: NYBSAGUY Re: Valve spring lengths - 04/08/20 3:49 pm
Hi Mike,

Have you tried Phil Pearson? He is local to you, and is easily the best resource in the UK

Give him a call and he will tell you what you need to know.

A lot of guys on this site use Mike Reilly in Brisbane, Australia, who also has a lot of parts.

Good luck.
Posted By: Kerry W Re: Valve spring lengths - 04/09/20 4:12 am
Talk to Phil P. I had a couple of sets of recently manufactured 'good' sets of springs when I turned up at his door to have him build my DBD engine. He used his own version, known what they were and how they were made. They weren't expensive - I took his advice and used his springs.

I'm sure Phil will supply springs and advice on preferred fitted lengths.
Posted By: 68triton Re: Valve spring lengths - 04/09/20 10:35 am
H Kerry, Yes, he done my cylinder head for me 6 years back. 20k miles and still good never had the the head off.

Posted By: 68triton Re: Valve spring lengths - 04/09/20 10:38 am
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